Girl’s fall leaves clues to earliest Americans
NEW YORK — Thousands of years ago, a teenage girl toppled into a deep hole in a Mexican cave and died. • Now, her skeleton and her DNA are bolstering the long-held theory that humans arrived in the Americas by way of a land bridge from Asia, scientists say.
The girl’s nearly complete skeleton was discovered by chance in 2007 by divers mapping water-filled caves north of the city of Tulum, in the eastern part of the Yucatan Peninsula. One day, they came across a huge chamber deep underground.
They named it Hoyo Negro, or black hole.
Months later, they returned and reached the floor of the 100-foot-deep chamber, which was littered with animal bones. They came across the girl’s skull on a ledge, lying upside down “with a perfect set of teeth and dark eye sockets looking back at us,” diver Alberto Nava said.
The divers named the skeleton Naia, after a water nymph of Greek mythology, and joined with a team of scientists to research the find.
The girl was 15 or 16 when she met her fate in the cave, which at that time was dry, researchers said. She may have been looking for water when she tumbled into the chamber 12,000 or 13,000 years ago, said lead study author James Chatters of Applied Paleoscience, a consulting firm in Bothell, Wash. Her pelvis was broken, suggesting she had fallen a long distance, he said.
The analysis of her remains, reported yesterday in the journal Science by researchers from the United States, Canada, Mexico and Denmark, addresses a puzzle about the settling of the Americas.
Most scientists say the first Americans came from Siberian ancestors who lived on an ancient land bridge, now submerged, that connected Asia to Alaska across the Bering Strait. They are thought to have entered the Americas sometime after 17,000 years ago from that land mass, called Beringia.
But the oldest skeletons — including Naia’s — have skulls that look much different from those of today’s native peoples. To some researchers, that suggests the first Americans came from elsewhere.
Naia provides a crucial link. DNA recovered from a molar contains a distinctive marker found in today’s native peoples, especially those in Chile and Argentina. The genetic signature is thought to have arisen among people living in Beringia, researchers said.
That shows that the early Americans and contemporary natives came from the same roots in Beringia, the researchers suggest. The anatomical differences reflect evolution in Beringia or the Americas, they said.
The finding does not rule out the idea that some ancient settlers came from another place, said Deborah Bolnick, a study author from the University of Texas at Austin.
Last February, other researchers reported that DNA from a baby buried in Montana more than 12,000 years ago showed a close genetic relationship to modern-day native peoples in Central and South America. An author of that study, Mike Waters of Texas A&M University, said the Mexican finding fits with the one in Montana.
However, Richard Jantz, a retired professor of forensic anthropology at the University of Tennessee in Knoxville, said he still believes early settlers arrived by boat from east Asia before any migration occurred via Beringia. That’s based on anatomical evidence, he said. The argument in the new paper “leaves a lot of unanswered questions,” he said in an email.